Solve
![-Dv Dv1 + (Bx Dv + By Dv1) Cos[θ] + (By Dv - Bx Dv1) Sin[θ] == 0](../HTMLFiles/index_156.gif){kind=small}
![Dv Dv2 - (Bx Dv + By Dv2) Cos[θ] + (By Dv - Bx Dv2) Sin[θ] == 0](../HTMLFiles/index_157.gif){kind=small}
